(57) The present invention concerns high efficiency reverse flow cyclones - with a tangential
entry of essentially rectangular section, sides a and b, the first parallel to the cyclone axis; a body of height H, with an upper cylindrical section of diameter D and height h and a lower inverted
cone with smaller base of diameter Db: and a cylindrical vortex finder of diameter De and length s - which may be used in laboratory or industrial conditions, whenever dedusting is
needed.
The inventor could obtain an empirical correlation to estimate particle turbulent
diffusivities under cyclone flow, through the use of a finite diffusivity theory which
was adjusted to laboratory, pilot-scale and industrial grade efficiency curves. This
correlation allows the design of reverse-flow cyclones of arbitrary geometry, as a
function of particle size distribution and operating conditions. A computer program
was made to obtain optimum designed reverse-flow cyclones, and two geometries have
been obtained, which respectively maximise collection efficiency and one ratio efficiency/costs.
The proposed geometries, defined as ratios of the above mentioned dimensions to the
cyclone inside diameter, differ from all geometries available in the literature, both
being significantly more efficient. For flow rates typical of industrial multicyclones,
the emissions should be 30-45% lower for the first family and 20-35% for the second,
as compared with emissions from high efficiency cyclones available. Laboratory-scale
tests with a similar geometry have confirmed the expected emissions reductions, at
similar levels of pressure drop.
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